fs/msdos/namei.c

   1 /*
   2  *  linux/fs/msdos/namei.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   6  *  Rewritten for constant inumbers 1999 by Al Viro
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/time.h>
  11 #include <linux/buffer_head.h>
  12 #include <linux/msdos_fs.h>
  13 #include <linux/smp_lock.h>
  14
  15 /* MS-DOS "device special files" */
  16 static const unsigned char *reserved_names[] = {
  17         "CON     ", "PRN     ", "NUL     ", "AUX     ",
  18         "LPT1    ", "LPT2    ", "LPT3    ", "LPT4    ",
  19         "COM1    ", "COM2    ", "COM3    ", "COM4    ",
  20         NULL
  21 };
  22
  23 /* Characters that are undesirable in an MS-DOS file name */
  24 static unsigned char bad_chars[] = "*?<>|\"";
  25 static unsigned char bad_if_strict_pc[] = "+=,; ";
  26 /* GEMDOS is less restrictive */
  27 static unsigned char bad_if_strict_atari[] = " ";
  28
  29 #define bad_if_strict(opts) \
  30         ((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc)
  31
  32 /***** Formats an MS-DOS file name. Rejects invalid names. */
  33 static int msdos_format_name(const unsigned char *name, int len,
  34                              unsigned char *res, struct fat_mount_options *opts)
  35         /*
  36          * name is the proposed name, len is its length, res is
  37          * the resulting name, opts->name_check is either (r)elaxed,
  38          * (n)ormal or (s)trict, opts->dotsOK allows dots at the
  39          * beginning of name (for hidden files)
  40          */
  41 {
  42         unsigned char *walk;
  43         const unsigned char **reserved;
  44         unsigned char c;
  45         int space;
  46
  47         if (name[0] == '.') {   /* dotfile because . and .. already done */
  48                 if (opts->dotsOK) {
  49                         /* Get rid of dot - test for it elsewhere */
  50                         name++;
  51                         len--;
  52                 } else if (!opts->atari)
  53                         return -EINVAL;
  54         }
  55         /*
  56          * disallow names that _really_ start with a dot for MS-DOS,
  57          * GEMDOS does not care
  58          */
  59         space = !opts->atari;
  60         c = 0;
  61         for (walk = res; len && walk - res < 8; walk++) {
  62                 c = *name++;
  63                 len--;
  64                 if (opts->name_check != 'r' && strchr(bad_chars, c))
  65                         return -EINVAL;
  66                 if (opts->name_check == 's' && strchr(bad_if_strict(opts), c))
  67                         return -EINVAL;
  68                 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
  69                         return -EINVAL;
  70                 if (c < ' ' || c == ':' || c == '\\')
  71                         return -EINVAL;
  72         /*
  73          * 0xE5 is legal as a first character, but we must substitute
  74          * 0x05 because 0xE5 marks deleted files.  Yes, DOS really
  75          * does this.
  76          * It seems that Microsoft hacked DOS to support non-US
  77          * characters after the 0xE5 character was already in use to
  78          * mark deleted files.
  79          */
  80                 if ((res == walk) && (c == 0xE5))
  81                         c = 0x05;
  82                 if (c == '.')
  83                         break;
  84                 space = (c == ' ');
  85                 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
  86         }
  87         if (space)
  88                 return -EINVAL;
  89         if (opts->name_check == 's' && len && c != '.') {
  90                 c = *name++;
  91                 len--;
  92                 if (c != '.')
  93                         return -EINVAL;
  94         }
  95         while (c != '.' && len--)
  96                 c = *name++;
  97         if (c == '.') {
  98                 while (walk - res < 8)
  99                         *walk++ = ' ';
 100                 while (len > 0 && walk - res < MSDOS_NAME) {
 101                         c = *name++;
 102                         len--;
 103                         if (opts->name_check != 'r' && strchr(bad_chars, c))
 104                                 return -EINVAL;
 105                         if (opts->name_check == 's' &&
 106                             strchr(bad_if_strict(opts), c))
 107                                 return -EINVAL;
 108                         if (c < ' ' || c == ':' || c == '\\')
 109                                 return -EINVAL;
 110                         if (c == '.') {
 111                                 if (opts->name_check == 's')
 112                                         return -EINVAL;
 113                                 break;
 114                         }
 115                         if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
 116                                 return -EINVAL;
 117                         space = c == ' ';
 118                         if (!opts->nocase && c >= 'a' && c <= 'z')
 119                                 *walk++ = c - 32;
 120                         else
 121                                 *walk++ = c;
 122                 }
 123                 if (space)
 124                         return -EINVAL;
 125                 if (opts->name_check == 's' && len)
 126                         return -EINVAL;
 127         }
 128         while (walk - res < MSDOS_NAME)
 129                 *walk++ = ' ';
 130         if (!opts->atari)
 131                 /* GEMDOS is less stupid and has no reserved names */
 132                 for (reserved = reserved_names; *reserved; reserved++)
 133                         if (!strncmp(res, *reserved, 8))
 134                                 return -EINVAL;
 135         return 0;
 136 }
 137
 138 /***** Locates a directory entry.  Uses unformatted name. */
 139 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
 140                       struct fat_slot_info *sinfo)
 141 {
 142         struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 143         unsigned char msdos_name[MSDOS_NAME];
 144         int err;
 145
 146         err = msdos_format_name(name, len, msdos_name, &sbi->options);
 147         if (err)
 148                 return -ENOENT;
 149
 150         err = fat_scan(dir, msdos_name, sinfo);
 151         if (!err && sbi->options.dotsOK) {
 152                 if (name[0] == '.') {
 153                         if (!(sinfo->de->attr & ATTR_HIDDEN))
 154                                 err = -ENOENT;
 155                 } else {
 156                         if (sinfo->de->attr & ATTR_HIDDEN)
 157                                 err = -ENOENT;
 158                 }
 159                 if (err)
 160                         brelse(sinfo->bh);
 161         }
 162         return err;
 163 }
 164
 165 /*
 166  * Compute the hash for the msdos name corresponding to the dentry.
 167  * Note: if the name is invalid, we leave the hash code unchanged so
 168  * that the existing dentry can be used. The msdos fs routines will
 169  * return ENOENT or EINVAL as appropriate.
 170  */
 171 static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
 172 {
 173         struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
 174         unsigned char msdos_name[MSDOS_NAME];
 175         int error;
 176
 177         error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
 178         if (!error)
 179                 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
 180         return 0;
 181 }
 182
 183 /*
 184  * Compare two msdos names. If either of the names are invalid,
 185  * we fall back to doing the standard name comparison.
 186  */
 187 static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
 188 {
 189         struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
 190         unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
 191         int error;
 192
 193         error = msdos_format_name(a->name, a->len, a_msdos_name, options);
 194         if (error)
 195                 goto old_compare;
 196         error = msdos_format_name(b->name, b->len, b_msdos_name, options);
 197         if (error)
 198                 goto old_compare;
 199         error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
 200 out:
 201         return error;
 202
 203 old_compare:
 204         error = 1;
 205         if (a->len == b->len)
 206                 error = memcmp(a->name, b->name, a->len);
 207         goto out;
 208 }
 209
 210 static struct dentry_operations msdos_dentry_operations = {
 211         .d_hash         = msdos_hash,
 212         .d_compare      = msdos_cmp,
 213 };
 214
 215 /*
 216  * AV. Wrappers for FAT sb operations. Is it wise?
 217  */
 218
 219 /***** Get inode using directory and name */
 220 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
 221                                    struct nameidata *nd)
 222 {
 223         struct super_block *sb = dir->i_sb;
 224         struct fat_slot_info sinfo;
 225         struct inode *inode = NULL;
 226         int res;
 227
 228         dentry->d_op = &msdos_dentry_operations;
 229
 230         lock_kernel();
 231         res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 232         if (res == -ENOENT)
 233                 goto add;
 234         if (res < 0)
 235                 goto out;
 236         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 237         brelse(sinfo.bh);
 238         if (IS_ERR(inode)) {
 239                 res = PTR_ERR(inode);
 240                 goto out;
 241         }
 242 add:
 243         res = 0;
 244         dentry = d_splice_alias(inode, dentry);
 245         if (dentry)
 246                 dentry->d_op = &msdos_dentry_operations;
 247 out:
 248         unlock_kernel();
 249         if (!res)
 250                 return dentry;
 251         return ERR_PTR(res);
 252 }
 253
 254 /***** Creates a directory entry (name is already formatted). */
 255 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
 256                            int is_dir, int is_hid, int cluster,
 257                            struct timespec *ts, struct fat_slot_info *sinfo)
 258 {
 259         struct msdos_dir_entry de;
 260         __le16 time, date;
 261         int err;
 262
 263         memcpy(de.name, name, MSDOS_NAME);
 264         de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 265         if (is_hid)
 266                 de.attr |= ATTR_HIDDEN;
 267         de.lcase = 0;
 268         fat_date_unix2dos(ts->tv_sec, &time, &date);
 269         de.cdate = de.adate = 0;
 270         de.ctime = 0;
 271         de.ctime_cs = 0;
 272         de.time = time;
 273         de.date = date;
 274         de.start = cpu_to_le16(cluster);
 275         de.starthi = cpu_to_le16(cluster >> 16);
 276         de.size = 0;
 277
 278         err = fat_add_entries(dir, &de, 1, sinfo);
 279         if (err)
 280                 return err;
 281
 282         dir->i_ctime = dir->i_mtime = *ts;
 283         if (IS_DIRSYNC(dir))
 284                 (void)fat_sync_inode(dir);
 285         else
 286                 mark_inode_dirty(dir);
 287
 288         return 0;
 289 }
 290
 291 /***** Create a file */
 292 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
 293                         struct nameidata *nd)
 294 {
 295         struct super_block *sb = dir->i_sb;
 296         struct inode *inode;
 297         struct fat_slot_info sinfo;
 298         struct timespec ts;
 299         unsigned char msdos_name[MSDOS_NAME];
 300         int err, is_hid;
 301
 302         lock_kernel();
 303
 304         err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 305                                 msdos_name, &MSDOS_SB(sb)->options);
 306         if (err)
 307                 goto out;
 308         is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 309         /* Have to do it due to foo vs. .foo conflicts */
 310         if (!fat_scan(dir, msdos_name, &sinfo)) {
 311                 brelse(sinfo.bh);
 312                 err = -EINVAL;
 313                 goto out;
 314         }
 315
 316         ts = CURRENT_TIME_SEC;
 317         err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
 318         if (err)
 319                 goto out;
 320         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 321         brelse(sinfo.bh);
 322         if (IS_ERR(inode)) {
 323                 err = PTR_ERR(inode);
 324                 goto out;
 325         }
 326         inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 327         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 328
 329         d_instantiate(dentry, inode);
 330 out:
 331         unlock_kernel();
 332         return err;
 333 }
 334
 335 /***** Remove a directory */
 336 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 337 {
 338         struct inode *inode = dentry->d_inode;
 339         struct fat_slot_info sinfo;
 340         int err;
 341
 342         lock_kernel();
 343         /*
 344          * Check whether the directory is not in use, then check
 345          * whether it is empty.
 346          */
 347         err = fat_dir_empty(inode);
 348         if (err)
 349                 goto out;
 350         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 351         if (err)
 352                 goto out;
 353
 354         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 355         if (err)
 356                 goto out;
 357         dir->i_nlink--;
 358
 359         inode->i_nlink = 0;
 360         inode->i_ctime = CURRENT_TIME_SEC;
 361         fat_detach(inode);
 362 out:
 363         unlock_kernel();
 364
 365         return err;
 366 }
 367
 368 /***** Make a directory */
 369 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 370 {
 371         struct super_block *sb = dir->i_sb;
 372         struct fat_slot_info sinfo;
 373         struct inode *inode;
 374         unsigned char msdos_name[MSDOS_NAME];
 375         struct timespec ts;
 376         int err, is_hid, cluster;
 377
 378         lock_kernel();
 379
 380         err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 381                                 msdos_name, &MSDOS_SB(sb)->options);
 382         if (err)
 383                 goto out;
 384         is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 385         /* foo vs .foo situation */
 386         if (!fat_scan(dir, msdos_name, &sinfo)) {
 387                 brelse(sinfo.bh);
 388                 err = -EINVAL;
 389                 goto out;
 390         }
 391
 392         ts = CURRENT_TIME_SEC;
 393         cluster = fat_alloc_new_dir(dir, &ts);
 394         if (cluster < 0) {
 395                 err = cluster;
 396                 goto out;
 397         }
 398         err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
 399         if (err)
 400                 goto out_free;
 401         dir->i_nlink++;
 402
 403         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 404         brelse(sinfo.bh);
 405         if (IS_ERR(inode)) {
 406                 err = PTR_ERR(inode);
 407                 /* the directory was completed, just return a error */
 408                 goto out;
 409         }
 410         inode->i_nlink = 2;
 411         inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 412         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 413
 414         d_instantiate(dentry, inode);
 415
 416         unlock_kernel();
 417         return 0;
 418
 419 out_free:
 420         fat_free_clusters(dir, cluster);
 421 out:
 422         unlock_kernel();
 423         return err;
 424 }
 425
 426 /***** Unlink a file */
 427 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
 428 {
 429         struct inode *inode = dentry->d_inode;
 430         struct fat_slot_info sinfo;
 431         int err;
 432
 433         lock_kernel();
 434         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 435         if (err)
 436                 goto out;
 437
 438         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 439         if (err)
 440                 goto out;
 441         inode->i_nlink = 0;
 442         inode->i_ctime = CURRENT_TIME_SEC;
 443         fat_detach(inode);
 444 out:
 445         unlock_kernel();
 446
 447         return err;
 448 }
 449
 450 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 451                            struct dentry *old_dentry,
 452                            struct inode *new_dir, unsigned char *new_name,
 453                            struct dentry *new_dentry, int is_hid)
 454 {
 455         struct buffer_head *dotdot_bh;
 456         struct msdos_dir_entry *dotdot_de;
 457         struct inode *old_inode, *new_inode;
 458         struct fat_slot_info old_sinfo, sinfo;
 459         struct timespec ts;
 460         loff_t dotdot_i_pos, new_i_pos;
 461         int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
 462
 463         old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 464         old_inode = old_dentry->d_inode;
 465         new_inode = new_dentry->d_inode;
 466
 467         err = fat_scan(old_dir, old_name, &old_sinfo);
 468         if (err) {
 469                 err = -EIO;
 470                 goto out;
 471         }
 472
 473         is_dir = S_ISDIR(old_inode->i_mode);
 474         update_dotdot = (is_dir && old_dir != new_dir);
 475         if (update_dotdot) {
 476                 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
 477                                          &dotdot_i_pos) < 0) {
 478                         err = -EIO;
 479                         goto out;
 480                 }
 481         }
 482
 483         old_attrs = MSDOS_I(old_inode)->i_attrs;
 484         err = fat_scan(new_dir, new_name, &sinfo);
 485         if (!err) {
 486                 if (!new_inode) {
 487                         /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
 488                         if (sinfo.de != old_sinfo.de) {
 489                                 err = -EINVAL;
 490                                 goto out;
 491                         }
 492                         if (is_hid)
 493                                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 494                         else
 495                                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 496                         if (IS_DIRSYNC(old_dir)) {
 497                                 err = fat_sync_inode(old_inode);
 498                                 if (err) {
 499                                         MSDOS_I(old_inode)->i_attrs = old_attrs;
 500                                         goto out;
 501                                 }
 502                         } else
 503                                 mark_inode_dirty(old_inode);
 504
 505                         old_dir->i_version++;
 506                         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 507                         if (IS_DIRSYNC(old_dir))
 508                                 (void)fat_sync_inode(old_dir);
 509                         else
 510                                 mark_inode_dirty(old_dir);
 511                         goto out;
 512                 }
 513         }
 514
 515         ts = CURRENT_TIME_SEC;
 516         if (new_inode) {
 517                 if (err)
 518                         goto out;
 519                 if (is_dir) {
 520                         err = fat_dir_empty(new_inode);
 521                         if (err)
 522                                 goto out;
 523                 }
 524                 new_i_pos = MSDOS_I(new_inode)->i_pos;
 525                 fat_detach(new_inode);
 526         } else {
 527                 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
 528                                       &ts, &sinfo);
 529                 if (err)
 530                         goto out;
 531                 new_i_pos = sinfo.i_pos;
 532         }
 533         new_dir->i_version++;
 534
 535         fat_detach(old_inode);
 536         fat_attach(old_inode, new_i_pos);
 537         if (is_hid)
 538                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 539         else
 540                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 541         if (IS_DIRSYNC(new_dir)) {
 542                 err = fat_sync_inode(old_inode);
 543                 if (err)
 544                         goto error_inode;
 545         } else
 546                 mark_inode_dirty(old_inode);
 547
 548         if (update_dotdot) {
 549                 int start = MSDOS_I(new_dir)->i_logstart;
 550                 dotdot_de->start = cpu_to_le16(start);
 551                 dotdot_de->starthi = cpu_to_le16(start >> 16);
 552                 mark_buffer_dirty(dotdot_bh);
 553                 if (IS_DIRSYNC(new_dir)) {
 554                         err = sync_dirty_buffer(dotdot_bh);
 555                         if (err)
 556                                 goto error_dotdot;
 557                 }
 558                 old_dir->i_nlink--;
 559                 if (!new_inode)
 560                         new_dir->i_nlink++;
 561         }
 562
 563         err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
 564         old_sinfo.bh = NULL;
 565         if (err)
 566                 goto error_dotdot;
 567         old_dir->i_version++;
 568         old_dir->i_ctime = old_dir->i_mtime = ts;
 569         if (IS_DIRSYNC(old_dir))
 570                 (void)fat_sync_inode(old_dir);
 571         else
 572                 mark_inode_dirty(old_dir);
 573
 574         if (new_inode) {
 575                 if (is_dir)
 576                         new_inode->i_nlink -= 2;
 577                 else
 578                         new_inode->i_nlink--;
 579                 new_inode->i_ctime = ts;
 580         }
 581 out:
 582         brelse(sinfo.bh);
 583         brelse(dotdot_bh);
 584         brelse(old_sinfo.bh);
 585         return err;
 586
 587 error_dotdot:
 588         /* data cluster is shared, serious corruption */
 589         corrupt = 1;
 590
 591         if (update_dotdot) {
 592                 int start = MSDOS_I(old_dir)->i_logstart;
 593                 dotdot_de->start = cpu_to_le16(start);
 594                 dotdot_de->starthi = cpu_to_le16(start >> 16);
 595                 mark_buffer_dirty(dotdot_bh);
 596                 corrupt |= sync_dirty_buffer(dotdot_bh);
 597         }
 598 error_inode:
 599         fat_detach(old_inode);
 600         fat_attach(old_inode, old_sinfo.i_pos);
 601         MSDOS_I(old_inode)->i_attrs = old_attrs;
 602         if (new_inode) {
 603                 fat_attach(new_inode, new_i_pos);
 604                 if (corrupt)
 605                         corrupt |= fat_sync_inode(new_inode);
 606         } else {
 607                 /*
 608                  * If new entry was not sharing the data cluster, it
 609                  * shouldn't be serious corruption.
 610                  */
 611                 int err2 = fat_remove_entries(new_dir, &sinfo);
 612                 if (corrupt)
 613                         corrupt |= err2;
 614                 sinfo.bh = NULL;
 615         }
 616         if (corrupt < 0) {
 617                 fat_fs_panic(new_dir->i_sb,
 618                              "%s: Filesystem corrupted (i_pos %lld)",
 619                              __FUNCTION__, sinfo.i_pos);
 620         }
 621         goto out;
 622 }
 623
 624 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
 625 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
 626                         struct inode *new_dir, struct dentry *new_dentry)
 627 {
 628         unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
 629         int err, is_hid;
 630
 631         lock_kernel();
 632
 633         err = msdos_format_name(old_dentry->d_name.name,
 634                                 old_dentry->d_name.len, old_msdos_name,
 635                                 &MSDOS_SB(old_dir->i_sb)->options);
 636         if (err)
 637                 goto out;
 638         err = msdos_format_name(new_dentry->d_name.name,
 639                                 new_dentry->d_name.len, new_msdos_name,
 640                                 &MSDOS_SB(new_dir->i_sb)->options);
 641         if (err)
 642                 goto out;
 643
 644         is_hid =
 645              (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
 646
 647         err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
 648                               new_dir, new_msdos_name, new_dentry, is_hid);
 649 out:
 650         unlock_kernel();
 651         return err;
 652 }
 653
 654 static struct inode_operations msdos_dir_inode_operations = {
 655         .create         = msdos_create,
 656         .lookup         = msdos_lookup,
 657         .unlink         = msdos_unlink,
 658         .mkdir          = msdos_mkdir,
 659         .rmdir          = msdos_rmdir,
 660         .rename         = msdos_rename,
 661         .setattr        = fat_notify_change,
 662 };
 663
 664 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
 665 {
 666         int res;
 667
 668         res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
 669         if (res)
 670                 return res;
 671
 672         sb->s_flags |= MS_NOATIME;
 673         sb->s_root->d_op = &msdos_dentry_operations;
 674         return 0;
 675 }
 676
 677 static struct super_block *msdos_get_sb(struct file_system_type *fs_type,
 678                                         int flags, const char *dev_name,
 679                                         void *data)
 680 {
 681         return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
 682 }
 683
 684 static struct file_system_type msdos_fs_type = {
 685         .owner          = THIS_MODULE,
 686         .name           = "msdos",
 687         .get_sb         = msdos_get_sb,
 688         .kill_sb        = kill_block_super,
 689         .fs_flags       = FS_REQUIRES_DEV,
 690 };
 691
 692 static int __init init_msdos_fs(void)
 693 {
 694         return register_filesystem(&msdos_fs_type);
 695 }
 696
 697 static void __exit exit_msdos_fs(void)
 698 {
 699         unregister_filesystem(&msdos_fs_type);
 700 }
 701
 702 MODULE_LICENSE("GPL");
 703 MODULE_AUTHOR("Werner Almesberger");
 704 MODULE_DESCRIPTION("MS-DOS filesystem support");
 705
 706 module_init(init_msdos_fs)
 707 module_exit(exit_msdos_fs)